1. Today, anthropogenic impacts are causing a serious crisis for global biodiversity, with rates of extinction increasing at an unprecedented rate. Extinctions typically occur after a certain delay and understanding the mechanisms causing delays is a key challenge for both fundamental and applied perspectives. 2. Here, we make use of natural experiments, the isolation of lakes by land up-lift in Northern Scandinavia, to examine how yearly extinction rates are affected by time since isolation and a range of abiotic and biotic factors. 3. In this aim, we adapted a model of delayed species loss within isolated communities to test the effects of time since isolation, area, pH, depth and presence/absence of piscivores on extinction rates. 4. As expected, we found that small and/or young lakes experience a higher annual rate of extinctions per species than larger and/or older ones. Compared to previous studies that were conducted for either young (few thousand years ago) or very old (>10 000 years ago) isolates, we demonstrated over a large and continuous temporal scales (50-5000 yr), similar relationship between extinction rates and age. We also show that extinction rates are modified by local environmental factors such as a strong negative effect of increasing pH. 5. Our results urge for the need to consider the time since critical environmental changes occurred when studying extinction rates. In a wider perspective our study demonstrates the need to consider extinction debts when modeling future effects of climate change, land-use changes, or biological invasions on biodiversity.